1. Field of the Invention
The present invention relates to an automatic cleaning apparatus for a charger of an image forming system using the electrophotography, such as a copying machine, printer and like.
2. Related Background Art
Arranged around a photosensitive drum acting as an image bearing member of a copying machine, there are, for example, primary charger for uniformly charging the photosensitive drum, a transfer charger for transferring a toner image formed on the photosensitive drum onto a transfer sheet or recording medium, and the like.
The charger, such as the primary charger and the transfer charger has a corona wire(s) disposed in a space enclosed by a shield, and serves to generate the corona discharge directing toward the photosensitive drum by supplying the voltage to the corona wire, thereby applying the positive or negative charges to the photosensitive drum.
If the toner, oil mist dust or the like, existing in the system, has adhered to the corona wire, the correct discharge is disturbed, thereby making the formation of the proper image difficult. Thus, it is necessary to clean or remove the stains that have adhered to the corona wire.
In general, as shown in FIG. 4, a charger has an automatic cleaning apparatus comprising a pair of cleaning members 101 between which a corona wire 100 is held and which can slide along the corona wire 100 to clean the latter.
However, when the corona wire 100 is held or sandwiched between the cleaning members 101, spaces 103 are created around the corona wire 100 between the contacted surfaces 102 of the cleaning members, i.e., there arise areas where the cleaning members 101 and the corona wire 100 do not contact with each other. Accordingly, as shown in FIG. 5A, if the stains 110 are adhered around the corona wire 100, even after the corona wire 100 has been cleaned by the cleaning members 101, a portion of the stains 110 will remain on the corona wire 100, as shown in FIG. 5B. Consequently, the formation of the proper image cannot be effected by the charger having such a corona wire.